1. Field of the Invention
In general, the present invention relates to granular modeling materiel, such as play sand, that can be pressed together to form three-dimensional structures. More particularly, the present invention relates to granular modeling material made from polymer-coated particles.
2. Prior Art Description
People have played with beach sand and formed beach sand into structures throughout history. Beach sand has many characteristics that make it fun to play with. Sand is generally soft when loose, yet it can be manually compacted into hard dense formations. Furthermore, moist particles of sand tend to adhere to each other when compacted. Accordingly, three-dimensional structures can be easily made from compacted sand. It is because of the high play value of sand that many parents, day care centers, and community parks erect sand boxes in which children can play.
Although natural sand has many characteristics that add to its play value, natural sand also has certain unfavorable characteristics. For example, natural sand is highly abrasive. As such, natural sand can quickly scratch floors and mar furniture if it comes into contact with such objects. Sand also has a tendency to disrupt mechanical movements found in appliances, toys, electronic gadgets, and the like. Lastly, natural sand absorbs water and takes a long time to dry once it has absorbed water. Consequently, natural sand can readily harbor many contaminants, such as microbial life, that can thrive in moist sand.
In an attempt to reduce the negative characteristics of natural sand, manufacturers have begun to create artificial sand. Artificial sand is made from polymer compositions and tends to be hydrophobic. Accordingly, artificial sand dries quickly and tends not to adhere to most objects, such as skin. Furthermore, artificial sand is polymer-based and is far less hard and/or abrasive than is natural sand. Although artificial sand is softer and cleaner than natural sand, the particles of artificial sand tend not to cling together in the same manner as natural sand. Consequently, it is harder to compress artificial sand into structures that maintain their form. It is because of this characteristic that artificial sand is often played with underwater. Under water, the pressure of the water presses the particles of artificial sand together and enables the artificial sand to maintain complex shapes. However, once the artificial sand is lifted out of the water, the various particles fall away and the structure of any form is lost. A commercially sold example of such artificial sand that is intended to be played with underwater is sold under the name Aqua Sand® by Spin Master, Inc of Ontario, Canada.
A need therefore exists for an artificial sand composition that is hydrophobic, yet exhibits some particle adhesion characteristics in dry air. In this manner, forms can be created from the artificial sand in ambient air. This need is met by the present invention as described and claimed below.